A large organization was required to deal with the trade, and this was built up under the supervision of Captain Reginald G.H. Henderson, C.B., of the Anti-Submarine Division of the Naval Staff, working under Vice-Admiral (then Rear-Admiral) Sir Alexander Duff, head of the Division, in conference with the Commanders-in-Chief, Portsmouth and Plymouth, under whose direction and protection the convoys were run. The immunity of this trade, carried out in the infested waters of the English Channel, from successful attack by submarines was extraordinary. No doubt the small size of the vessels concerned and their comparatively shallow draught were a contributory cause to this immunity. The figures for the period March to August, 1917, show that 8,825 vessels crossed the Channel under convoy, and that only fourteen were lost. The history of the _Scandinavian and East Coast convoys_ dates back to the autumn of 1916, when heavy losses were being incurred amongst Scandinavian ships due to submarine attack. Thus in October, 1916, the losses amongst Norwegian and Swedish ships by submarine attack were more than three times as great as the previous highest monthly losses. Some fear existed that the neutral Scandinavian countries might refuse to run such risks and go to the extreme of prohibiting sailings. Towards the end of 1916, before I left the Fleet, a system of "protected" sailings was therefore introduced. In this system the Commander-in-Chief, Grand Fleet, fixed upon a number of alternative routes between Norway and the Shetland Islands, which were used by all vessels trading between Scandinavia and Allied countries. The particular route in use at any given moment was patrolled by the local forces from the Orkneys and Shetlands, assisted when possible by small craft from the Grand Fleet. The Admiral Commanding the Orkneys and Shetlands was placed in charge of the arrangements, which were carried out by the Senior Naval Officer at Lerwick, in the Shetland Islands. At this period the intention was that the shipping from Norway should sail at dusk, reach a certain rendezvous at dawn, and thence be escorted to Lerwick. The shipping from Lerwick sailed at dawn under protection, dispersed at dark, and reached the Norwegian coast at dawn. Difficulties, of course, arose in the event of bad weather, or when the slow speed of the ships prevented the passage of about 180 miles being made in approximately twenty-four hours, and by April, 1917, it was evident that further steps were necessary to meet these difficulties, which were again causing heavy losses. Early in April, then, by direction from the Admiralty, a conference was held at Longhope on the subject. Admiral Sir Frederick Brock, Commanding the Orkneys and Shetlands, presided, and representatives from the Admiralty and the Commands affected were present, and the adoption of a complete convoy system to include the whole trade between the East Coast and Norway was recommended.